This proposed study focuses on newborn screening for Critical Congenital Heart Disease (CCHD) using Pulse Oximetry, which was added to the recommended uniform screening panel (RUSP) in 2011. Challenges often face implementation of new medical screenings into the patient environment, in spite of proven effectiveness in research. Low implementation levels of screening can greatly diminish outcomes for infants, as undiagnosed CCHD can lead to greater mortality and morbidities, including developmental problems. Infants without CCHD will also be affected by low implementation because incorrect screening procedures can lead to false positive results, causing families to face anxiety and unnecessary costs for transport and further examination. Currently, over 99% of U.S. newborns are born in states that have individually mandated CCHD screening in the last 3 years, yet implementation levels in many states are low or unknown. In the study?s first aim, barriers and facilitators in the current CCHD screening implementation will be assessed through: (1) observation of CCHD screening practices at hospitals in the local area, (2) nationwide one-on-one interviews among nurse managers in nursery units, and (3) nationwide surveys of nursery nurses. A systematic assessment of multilevel implementation will be guided by the Consolidated Framework for Implementation Research (CFIR), serving as an organizational construct. Results will help tailor interventions to improve implementation. In order to estimate future implementation levels, the nurses? survey will be conducted at two time points (years three and five). For our second aim, we will use cost-effectiveness analysis (CEA). With CEA, the difference in cost-effectiveness between current and future years will be calculated. Results will determine whether diffusion (natural adoption of a technique over time) is enough to bring about desired levels of implementation, or if investment is needed to accomplish desired levels of cost-effective interventions. The Parent K01 is an important mechanism for reaching my career goal to become an independent investigator in health services research. Support will allow me to extend my research acumen into my primary focus of implementation science, from both a qualitative and quantitative approach. Up until this point, my focus and practice has been clinical and quantitative. K01 provides me with training in skills I have not had time or the opportunity to develop, including qualitative research interview methodologies, survey design and administration, and cost-effectiveness analysis. I hold an Assistant Professor position at Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, with access to many resources at UCLA Westwood, Charles R. Drew University, and RAND. Moreover, I have the support of an incredible team of outstanding mentors from these UCLA-associated institutions. Research in implementation science and cost- effectiveness analysis will drive my future career direction when I seek funding through an R01 mechanism.